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6mm ARC Bolt Gun Loadings

67rschev

Sergeant
Full Member
Minuteman
May 9, 2011
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Colorado
I have finished a 6mm ARC bolt action, and there's not a whole lot of data out. . Been fooling with the 6 arc in first a 18 inch and then a 22 in semi for the last year, so I have some baseline and experience with loading the cartridge. Did a shake down was with 10 rounds factory 108 eldm, and then a first ladder that started with Varget and the ( GAP ) Hornady 109 ELDM. Ran the ladder from 26 to 28, with depth at .020 of the lands. Liking what I am seeing, but worried I may be a bit over pressure. Hornady lists 28.1 to be max with the 108 eldm, I'm at 28. Sure seems the loads listed through Hornady seem to be much higher than other loading resources, such as Hodgdon. Ran it through GRT, and the program estimates 65 k using the 110 Atip ( modified in weight ) as the projectile. Brass looks perfect, but this is my first experience with the Nucleus receiver having no plunger ejector. Also, primers look slightly dimples in from pin strike. GRT estimates 26 inch barrel at 2822 fps and i was at ~2750, which would be about perfect.

Any one any experience with said combo or close, or could run this through Quickload if they have the time. Thanks in advance
 
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I started with the Bolt version first and now going to the Semi Auto route. In my Bolt gun: 24" Shaw 416R SS with 1-7 twist barrel. I found using H4895 for the 108 ELDM. Start at 26.6 and work up. Found a load (2770 fps with SD: 2.4) I found that H4895 for the heavier bullets worked better. Was not happy with Varget for the heavier bullets. Same results for the A-Tips.
 

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Thanks for the input, opposite paths ending in the same place. I've used the IMR 4895 in the past but not H. Also on hand, and in the mix I plan on working with RE15, Shootersworld Precision, and Leverevolution. Lever's been pretty good in the semi, just not a big fan of ball powder.

Here is the referred first work up with Varget, as stated it showed good promise. Watching them form as I was shooting, It felt like they were tightening up again at that 28 mark, maybe a little higher. Side note, brass and primer pockets were GTG at 28. Still nervous after running it through GRT

Load.jpg
 
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Worked up some loads checking out the 27 grain window, results were pretty favorable. Tried a couple groups neck sizing only top row, and second sets with a light FL and .002 shoulder bump middle row, and a set with .005 bump. Seems as if it liked a little shoulder set back. Going to tweak the neck tension a bit and then go after the 28 grain area, thinking it could be near as accurate. May swap around some primers, dunno which would be best for the combo. Been using CCI 400s, and have all the others to try. Any one see any appreciable gains from one primer to the next with this cartridge ?


27.jpg
 
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Ran a couple more ladders yesterday, the first was with Varget and 108 Bergers and the second was with 108 elds and RL15. Things of note, the barrel picked up on average ~50 to 60 fps after a thorough cleaning at the 75 round mark. I pulled a couple patches during the first 10 rounds of barrel break in, but this was like a light switch instant 50 fps. Varget is showing more / comparable speed at roughly half a grain less than the Reloader 15. Somewhat confirmed earlier ladder showing 27 and 28 grains having nice accuracy windows. A big mistake at 28.5 of RL15, the last shot of the ladder was a full 120fps off the rest. Must of pootched something with the powder in the reloading block.

Varget and Berger 108s


Berger Varget.jpg


RE15 and 108 ELDs

vld rl15.jpg
 
Loaded up a two sets of ten revisiting the previous post's Berger / Varget combo at 27.9, and a tenth over at 28. Printed some nice groups, both charge weights showing same POI, I'll call this GTG. Think I'm at my practical limit with a bipod and bag anyways. Going to continue working on the 109 eldms next. I think the barrel has now stopped speeding up, at round count ~120


thumbnail_IMG_3641.jpg
 
Midway came through for me, and the new (proper size) bushing showed up today. Got them all resized (again), and loaded up my first round of load development for my 16" Christensen Arms MPR. I'm running 1x fired and FL sized Hornady brass, CFE-223, CCI 400's, and Nosler 115 RDF's. I'm running all the way up to 29.0gr in 0.5 grain increments (first round of data is pressure baseline and finding a rough node pattern). I'll report back my findings.

In case someone else reads this in the future, DO NOT use bolt-gun load data in a gas gun. Bolt guns can handle a lot more pressure.

IMG_7792.jpeg
IMG_7787.jpeg
IMG_7788.jpeg
 
UPDATE Unfortunately, the 28.9 Varget load with the Berger 108s sped up on me considerably. I don't know if it is the barrel still breaking in, or some other issue with my load procedure and / or barrel cleaning. Was seeing 2900+, and it started to blow up the group a bit. It is throwing a shot out of the groups, opening them to the high 4s. and 5s. Brass was showing some overpresure and primer pockets are now a bit smoked at 6 firings.

Rimfire match season is starting, lot testing and preparation is using all my available range time. I have not tried tweaking the load, backing it down to that 2820 - 2850 window, hoping it will get that tenth or two back. Also have some fresh Starline and Lapua brass to work with.
 
I have finished a 6mm ARC bolt action, and there's not a whole lot of data out. . Been fooling with the 6 arc in first a 18 inch and then a 22 in semi for the last year, so I have some baseline and experience with loading the cartridge. Did a shake down was with 10 rounds factory 108 eldm, and then a first ladder that started with Varget and the ( GAP ) Hornady 109 ELDM. Ran the ladder from 26 to 28, with depth at .020 of the lands. Liking what I am seeing, but worried I may be a bit over pressure. Hornady lists 28.1 to be max with the 108 eldm, I'm at 28. Sure seems the loads listed through Hornady seem to be much higher than other loading resources, such as Hodgdon. Ran it through GRT, and the program estimates 65 k using the 110 Atip ( modified in weight ) as the projectile. Brass looks perfect, but this is my first experience with the Nucleus receiver having no plunger ejector. Also, primers look slightly dimples in from pin strike. GRT estimates 26 inch barrel at 2822 fps and i was at ~2750, which would be about perfect.

Any one any experience with said combo or close, or could run this through Quickload if they have the time. Thanks in advance
i have been crazy happy with 27g benchmark, 87g vmax, it's so easy- and 2925, 1/2" is easy and must be easy on barrel- got 9200 plus round on mpa 27" barrel, yest easy 1/2", youtube search this: prarie dog express v.103 send it"
 
I'm running 1x fired and FL sized Hornady brass, CFE-223, CCI 400's, and Nosler 115 RDF's. I'm running all the way up to 29.0gr in 0.5 grain increments (first round of data is pressure baseline and finding a rough node pattern). I'll report back my findings.
What load did you end up settling on? I figured the 115 class projectiles would be too much for the little ARC case.
 
What load did you end up settling on? I figured the 115 class projectiles would be too much for the little ARC case.